This research proposes continued development of instrumentation and procedures which will permit more accurate quantitative measurement of cardiac geometry using ultrasound. The previously developed transducer locator system will be used in a series of studies related to cardiac anatomy and performance. Techniques will be developed to acquire multiple 2-D scans with their spatial coordinates at various points in the cardiac cycle and from varous acoustic windows. Methods for three-dimensional reconstruction will be validated, as will procedures to calculate the volume and related parameters from the structure of interest. Several clinical problems will be addressed using these techniques including non-uniform contraction induced by coronary artery disease, and left ventricular aneursym. The results of this work should significantly improve the level of quantitation available from clinical ultrasound instruments and provide the basis for long-term studies using echocardiography.